A power steering mechanism comprises an electric assisting steering motor and a worm mounted on an output shaft of the said motor and meshing with a gear wheel for example attached to the steering column shaft or connected to the steering rack via an intermediate pinion.
In general, the power steering mechanism further comprises a system for automatically compensating for the wearing of the thread or threads of the worm and/or of the teeth of the associated gear wheel which may occur over the course of time. For further details, reference may, for example, be made to document DE-A1-100 53 183 which illustrates such a wear compensation system.
In that document, the wear compensation system notably comprises an eccentric mounted at one end of the worm via a rolling-contact bearing and coming into radial contact in the bore of a tubular housing, a rotation-proofing element mounted on the eccentric and a torsion spring mounted between the said rotation-proofing element and the eccentric and forming a means making it possible constantly to apply a circumferential force to the eccentric.
The wear compensation system described in that document has the notable disadvantage of requiring a great many operations when it is being mounted onto the worm. Further, it is necessary to provide a step of adjusting the relative angular orientation of the rotation-proofing element and of the eccentric so as to preload the torsion spring.
The present invention seeks to overcome these disadvantages.